Each individual breath—not just breathing rate—is closely linked to the pattern of electrical activity in brain regions tied to cognition, emotion and memory, according to a new study that could help explain how breathing disorders turn deadly.
For the study, published in the Journal of Neuroscience, researchers led by the University of California San Diego analyzed invasive brain recordings from 16 people undergoing clinical monitoring for treatment-resistant epilepsy. The team compared electrical activity recorded directly from the brain with detailed measurements of each person's breathing, including nasal airflow and chest and abdominal movement.
Rather than treating breathing as a steady rhythm measured only in breaths per minute, the team represented each breath as a wave-like pattern reflecting the rise and fall of airflow during inhalation and exhalation, then compared that shape to the corresponding pattern of brain activity.
The comparison revealed a much tighter coupling than previously known: variations such as a longer inhale, a slower exhale or a pause in breathing were mirrored in corresponding shifts in neural activity. This builds on earlier findings that breathing timing can influence attention and memory. For example, people tend to perform slightly better on memory tasks when they encounter information while inhaling rather than exhaling, and breath control techniques are already used to calm people experiencing PTSD symptoms.
"Every single breath is different," said Eena Kosik-Rose, the study's first author and a doctoral student in UC San Diego's Department of Cognitive Science. "You can pause your breathing for several seconds, take a super deep breath or have a shallow exhale. What we're showing is that those differences in the shape of each breath are reflected in the shape of brain activity."
The researchers say the findings could open a path toward better understanding conditions in which the breathing-brain relationship breaks down dangerously, including sudden unexpected death in epilepsy and sudden infant death syndrome.
The current study doesn't establish a way to predict SUDEP or SIDS, and because it relied on precise recordings taken directly from the brains of people already undergoing epilepsy monitoring, the findings will need to be tested using noninvasive methods in broader populations. Still, the discovery opens new research possibilities.
"Now that we know that there is this incredibly tight and rich coupling between the shape of each breath and the shape of each brainwave, there's a whole new world of options that we can explore," says Bradley Voytek, study co-author and professor and chair of the Department of Cognitive Science.
Data from UC San Diego